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Publisher/Editor; N. S. Cheek, Sr, aka *8r. Rigoraortis* : V1N3: Harch , 1991 

A Journal of VHF-UHF Scanner Technology i Engineering 

Published at: CQHHtronics Engineering; PO BOX 262478; San Diego, CA 92196 Copyright (c) 1991 (All Rights Reserved) $4.90 


HDD-16 UPDftTEs 6,499 Channels For The PRO-2004/5/6 

Despite ay otter to help with problems , there have been relatively 
tew requests associated with any of the Hods in Vol-1 of ay book. 
Perhaps the single greatest trouble spot, and it isn't great in 
the strictest sense of the word, is HOD-16, the 6,400 Channel 
Extended Heaory for the PRO-2904/5/6. I worked on a couple of 
scanners that had MOD-16 problems and offered helpful suggestions 
to a handful more. In all cases, the trouble with HOD-16 was 
easily remedied: one or more errors in the wiring and connection 
of the 28 necessary wires. 

Face it, when 23 wires sust solder into a space of only a couple 
of square inches, there is an excellent opportunity to literally 
get your wires crossed. And, one crossed pair of wires means TNO 
mistakes ! This type of mistake results in unpredictable, erratic 
operation, depending on which wires get crossed. In no event, 
however, has any serious harm been caused, though I have known the 
SRAH chip to blow out in a couple of cases because of errors in 
the wiring. Correct any wiring errors and start with a known good 
SRAH chip and 6,400-channel operation will be letter perfect! If 
you have put off adding 6,000 more channels to your PRO-2004/5/6 
for fear of making a serious mistake, relax! The instructions for 
HOD-16 in Voi-1 of ay SCANNER HQDIFICATION HANDBOOK are accurate 
and detailed. If you will patiently follow the instructions, step 
by step, you'll be successful. 

If you are following the directions in Vol-1 of ay SCANNER 
HQDIFICATION HANDBOOK , be sure to change the resistors, R1-R4, 
froa 1-k (or 4.7-k) to 47-k. Better still, wait for Vol-2 of the 
SCANNER HQDIFICATION HANDBOOK to coae out next aonth where there 
will be featured a Keyboard Heaory Block Controller (KHBC) for 
HQD-16, very siailar to this aonth's Keyboard Extended Function 
Switch. In fact, the KHBC (HOD-28), eliminates the need for any 
external switches to control the 16 Blocks of 400 channels ea. 
You siaply press two Keyboard keys and the rest is autoaatic. No 
external switches required!!! 


CRB Research Books has informal ly announced that Voluae 2 of ay 
SCANNER HQDIFICATION HANDBOOK will be available in early April, 
1991. It will be sold at sail order dealers around the country, 
directly froa the publisher, or best still, and froa nowhere else, 
you can get a personally autographed copy directly froa me. Orders 
now being accepted for either Vol-1 or Vol-2 at $17.95 ea, plus 
$3.09 (USA) first class shipping; $4.00 Canada or $5.00, other 
foreign. Allow extra for foreign Air Hail. All ay books 
purchased froa me will be autographed and will contain a notice 
(if necessary) of any pertinent errors or problems to be pen & ink 
corrected. NOTE: Vol-2 is not expected to be shipped before 
early-aid April, but your advance order with payaent will receive 

priority attention; first coae, first served, when available. It 
is probable, since I aa the author, that I'll have Vol-2 ready for 
shipment before other dealers around the country. You can use the 
Sub Order Blank on Page 7 to order ay books. 

Please don t confuse Vol-2 with Vol-1. Ruaors are circulating how 
Voi-2 is only an aaended version of Vol-1. Ha ha! No way! Vol-2 
takes up where Vol-1 leaves off. Short of a brief review of Vol-1 
with error corrections and new ways of doing old things, Vol-2 
takes off into uncharted territory with new aods, new hints and 
new tricks. If you're a Hacker, you'll need both. 

This corner of 'THE NORLD SCANNER REPORT ' will keep both volumes 
of ay books updated, so stay tuned here! Next aonth, or after 
Vol-2 has been released, I'll present a review of it for your 

< < < < * > > > > 

Public Hessage (RECEIVED; 

Message I 5598 * SHORT-NAVE/SCANNER * 

To : All 

Froa : Ken Hoehn 

Subject : AQR scanners froa ACE 

Date : 91/02/17, 01:44:80 

Beware of purchasing AQR scanners froa ACE loss, of Indianapolis, 
IN. I have gone through literal hell getting a probiea resolved 
there. They take the $, and get to the probiea when and IF they 
feel like it. In research, I find that the AOR-ACE relationship 
is not so rosy either, but ACE has the US aarket locked up. 

If you buy it, good luck. If you need it fixed (and several have 
coae to us with initial failures. .. .better luck. Try sending it 
to your local high school electronics class. ...the repair will 
likely be better! — == Ken ==— 

— TASHAIL v2. 38 

* Origin: The «< Air Studio ») BBS 313-546-7045 (1:120/216) 

EDITOR'S NOTE: The above aessage was taken fro i the Shortmave & 
Scanner Echo of the International FidoNet f a uorld&ide public 
coaputer network in » hich I participates It is reproduced for you 
here as a follow up to last aonth's article on the AR-3000 by 
a Professor Peabody” . This aessage should not be construed as the 
final say-so about AOR scanners or ACE Coaaunications, but it does 
represent one person's opinion . I will reproduce i ore Material , 
pro and con, on various subjects froa the FidoNet occasional! y. 


Coaputer BBS's, the FidoNet and radio are discussed at greater 
length in ay coming Vol-2 of the SCANNER MODIFICATION HANDBOOK , 
but if you have a computer with a aodea, you're all set for sose 

direct communications with me now if you like. I am available to 
you on three computer bulletin boards in the San Diego area. You 
can leave me either a private E-Hail or a public message as you 
see fit, and I will usually answer within 24 hours on the first 
two BBS's. I check into the third one listed about once a week. 
All three have great Scanner Conferences in which I participate. 
If you call, follow the simple log-on directions and we'll chat! 
The 1st & last are 24-hr/day BBS's; the 2nd is off from 8pa-12pa, 
Pacific Time. (619) 560-7659; (619) 273-6339; (619) 275-6129 



Have you ever flipped a wall light switch in your home only to 
wish that it would control not only the lights, but also a TV, 
maybe flush the toilet, start the dishwasher, open the garage door 
and shut off the kids' stereo system? You know, one switch to do 
many different things? Mental telepathy might do it if you're 
capable, but for the unadept, a few cheap chips and a handful of 
junkbcx parts can be wired together to make the Keyboard of your 
scanner do lots more than just what the manufacturer intended! 

Gk, let me explain..... See, your scanner's keyboard has anywhere 
from 15 to 29 push-button switches on it, each one controlling a 
different function. Fine 'n dandy until you do some modifications 
and extra functions which require external control. A conventional 
method for any necessary extra switching is to drill some holes 
and install toggle switches of one sort or another. I prefer the 
newfangled DIP switches, but they're hard to install and a mess of 
things can be made if you're not careful. Toggle switches are 
easy to install, but may the Cosmos help you if the drill bit 
suddenly breaks through the chassis and runs amok inside the 
scanner before you have the presence of mind to shut it off. 

Retrofitted toggle switches seem to never match up with the design 
scheme of the scanner's face plate, or you have to install them in 
the rear panel out of sight (and mind) and are most difficult to 
reach for casual control of things. Eureka! I haye developed a 
super slick method of controlling various modifications and extra 
functions, and absolutely no external switches of any kind are 
required! Ne'll just use the scanner's Keyboard in such a manner 
that won't disrupt normal scanner functions and which will still 
allow you to turn things on and off at will. The secret is the 
use of TWO KEYS simultaneously! 

There is at least one or two keys on most scanners that, when 
pressed, do absolutely nothing under normal conditions. One of 
these keys is the CLEAR key and another is the ENTER key. For 
example, turn your scanner ON and immediately press either CLEAR 
or ENTER. Nothing out of the ordinary happens, right? If so, the 
rest of this article is for YOU, because we can use the CLEAR 
and/or ENTER keys in conjunction with certain other keys to 
generate a switching sequence for controlling add-ons such as an 
Automatic Tape Recorder Switch; Extended Delay Function, Data 
Squelch, 6,438 Channels of Extended Memory, or most anything else 
that requires an external switch of some sort or another! 

The interesting thing about the CLEAR and ENTER keys is that not 
only do they do nothing when pressed under normal circumstances, 

but they also tell the CPU to ignore any other key if pressed at 
the same time! So try this to see what I mean: first press and 
hold the CLEAR key followed by the PROGRAM key (or any other key). 
Nothing happens! Wonderful, because we will sake use of a dual 
keypress in a simple logic circuit to operate an electronic switch 
which is good enough for many switching requirements! You won't 
have to drill any holes or deface the scanner at all unless you'd 
like some neat looking LEDs to indicate what switch functions are 
on or off. In that case, you'll have to drill some t / 9 * holes for 
T-l sized LEDs, but this is not necessary if you're not turned on 
by drilling holes. You'll just have to remember what has been 
switched on or off which shouldn't be all that difficult. 
Otherwise, install LEDs as shown herein for a super sporty and 
great looking effect! 

The Keyboard Extended Function Switch features four unique and 
separate electronic switches that can control most low current 
functions typical of cy scanner modifications. You will operate 
these switch functions by merely pressing the scanner's CLEAR key 
and one other key at the same time. Press both for ON; press both 
again for OFF. How much simpler or more aesthetic can it be? 


The heart and soul of the KEFS is the 4066 “bilateral 9 (two-way) 
electronic switch chip which comes in a standard 14-pin DIP 
package. Nothing unusual about the wiring and layout of this neat 
chip except that it contains the equivalent of four SPST toggle 
switches. Four of the 4066 s pins are for control of the 
switches; eight pins for the actual switches; and then there's a 
ground pin and a power supply pin for a total of 14 pins. 

The logic of my KEFS consists of a Quad Dual Input AND chip, 
(74HC88) which feeds two Dual Type D Flip-Flops, (4013). Each 
segment of the AND chip required two inputs to generate one 
output. This creates the dual keypress logic. My KEFS ignores 
normal scanner keypresses and the scanner ignores the KEFS dual 
keypresses!. Each output of the AND chip triggers a corresponding 
Flip-Flop to trigger the pertinent switch segment of the 4066 
chip. The design is such that when you first turn on your 
scanner, all switch segments are OFF. This ensures that your 
scanner fires up normally as the manufacturer intended. You can 
then select whichever of the four switch combinations you desire 
to perform intended functions. The circuit is simple enough, and 
even if you don't know a thing about digital electronics, you can 
still achieve success if you follow ay steps and diagrams here. 

If, for any reason, you do not wish to perform this project 
yourself, anyone with amateur technical ability can do it for you. 
I will offer the Keyboard Extended Function Switch as MOD-47 of my 
standard modification services. The KEFS will also be available 
as a preassembled and tested circuit board, ready for you, me or 
someone else to install. Since this modification is so new, 
prices and availability are not yet certain, but you can contact 
me for details which should be available soon. Now let's build 
the Keyboard Extended Function Switch to control whatever in your 
scanner needs to be controlled. Refer to the Parts List, the 
diagrams and pictorials, and the steps of procedure on the 
following pages. Nothing is terribly critical, but work carefully 
and don't deviate from the Parts List. 


H1N 3 - Page 2 



Sym Quan 


Radio Shack 
Cat Number 



IC; 74HC88 or 74C08; Dual Input Quad AND 


U-2, 3 


IC; 4813; Dual Type D Flip-Flop 




IC; 4066; Quad Bilateral Switch 


Ux 1-4 


IC DIP sockets; 14-pin 




0.47-uF/35vdc capacitor; tantalus 




2.2-uF/35vdc capacitor; tantalum 




18-k resistor 




188-k resistor 




1.5-k resistor 




T-l sized LEDs; your choice of color 

276-026 typ 



Hookup wire; assorted color codes 




"Perf Board" 




Solid copper wire; 18-ga; small quantity 




Solid copper wire; 24-ga; board wiring 




Heat Shrink Tubing; for neat wire bundling 278-1627 



1-k resistor 




18-k resistor 



1. Build the KEFS on a piece of "perf board 3 measuring about 
l 1 / 2 n x 2 l / 4 \ Use the general layout as shown. 

2. Solder to 14-pin DIP IC sockets and plug the chips in only 
after the KEFS board is completed and inspected for errors. 

3. Begin by wiring together the Pin 7's of all four chips. This 
will be KEFS ground. Also ground pins 4 and 10 of U-2 and 
U-3, the 4813 's. 

4. Hire together the Pin 14 's of all four chips. This will be 
the +5v power supply buss. 

5. Next install and solder in place all capacitors, followed by 
the resistors. You can eliminate resistors R9-R12 if you 
don't want external LED indicators. Otherwise, install R9-R12 
on end with a free end of each pointing up fro# the KEFS 
circuit board. He'll put wires to these 4 resistors later for 
the LED assembly that will be installed in the front panel. 

6. You will probably have to use "jumper n wires to cross other 
wires on your KEFS circuit board. Try to use both sides of 
the board for jumpering as shown in the photos to minimize the 
use of messy insulated wiring on the board. Fully complete 
the KEFS board at this tise before proceeding further. 

7. Set up a color coded wiring scheme for the Keyboard Switch 
Control; LEDs; Switch Input/Output; +5v power and ground wires 
so that you can tell the difference among them later. Each of 
the wires should be about 6“-10 n in length for starters. You 
can trim them to length later. A great source of color coded 
hookup wires is Radio Shack's #273-776. Strip the outer 
insulation k shield k salvage the wires for hookups! 

A. Solder a color coded pair of wires to U-l, Pins 1 k 2. Solder 

a similar, but different color coded pair of wires to li-4, 

Pins 1 k 2. Solder a similar color coded wire to the free end 
of R-9. These wires are associated with "Switch A a . 

B. Solder a color coded pair of wires to U-l, Pins 4 k 5. Solder 

a similar, but different color coded pair of wires to U-4, 

Pins 3 k 4. Solder a similar color coded wire to the free end 
of R-10. These wires are associated with "Switch B\ 

C. Solder a color coded pair of wires to U-l, Pins 9 k 10. 
Solder a similar, but different color coded pair of wires to 
U-4, Pins 8 & 9. Solder a similar color coded wire to the 
free end of R-ll. These wires are associated with "Switch C a . 

D. Solder a color coded pair of wires to U-l, Pins 12 k 13. 
Solder a similar, but different color coded pair of wires to 
U-4, Pins 18 k 11. Solder a similar color coded wire to the 
free end of R-12. These wires are associated with "Switch D". 

E. Solder a color coded wire to the +5v power buss that connects 
the Pins 114 of all four chips on the KEFS board.. 

F. Solder two color coded wires to the ground buss that connects 
the Pins #7 of all four chips. 

S. Route one of the ground wires connected in Step 7.F along with 
the four wires that were connected to R9-R12 in Steps 7. A - 
7.D above. Make a bundle of these five wires for routing to 
the LED assembly later. Skip this step and one of the two 
ground wires if you do not want the LED Indicator. 

H. Depending on HQH you want to install the KEFS in your scanner, 
solder a stiff, bare copper wire (18-ga) about 3" long to the 
ground buss that connects the Pins #7 of all four chips. This 
stiff copper wire can later be soldered to the scanner's inner 
metal chassis or to a PCB ground trace for a nice, shock-free 
installation that will permit easy removal at any time needed. 
Otherwise, you can mount the KEFS board using machine nuts, 
bolts and standoffs as desired. 


I. Bundle together the Keyboard Control wires that were soldered 
to U-l in Steps 7. A - 7.D above. Strip I / 4 “ of insulation 
from the ends of each of the eight wires and twist together 
the bare ends of each wire pair. (Keep each pair separate!) 
Solder a 10,800-ohm (18-k) resistor to each of the wire pair 
junctions. Solder together the free ends of the four 
resistors into a common junction. Then solder this common 
resistor junction to a ground on the KEFS board. NOTE: This 
Step is temporary for testing and later the resistors will be 
removed and the wire pairs will be separated. 

J. Bundle together the 4866 Switch In-Out wire pairs that were 
soldered to U-4 in Steps 7. A - 7.D above. Strip 1 / 4 " of 
insulation from the ends of each wire pair and leave the bare 
ends close together but not touching. 


V1R3 - Page 3 

K, It an LED Indicator is desired, then select tour T-l sized 
LEDs of your color choice (orange, green, yellow & red?) and 
temporarily solder all the cathodes together, and solder that 
common cathode junction to one of the ground wires connected 
in Step 7.F above. Then solder the wire from R-9 to the anode 
of LED "A\ Solder the wire from R-10 to the anode of LED H 8 n . 
Solder the wire from R-ii to the anode of LED B C a . Solder the 
wire from R-12 to the anode of LED “D". 


The KEFS board should NOT be installed in your scanner at this 

time. Be will test it for proper operation prior to installation. 

8. You should have a 5-voit DC power supply for testing the KEFS 

board, but if none is available, you can use the one in your 

scanner. See below. You could also rig three flashlight 
batteries in series for 4.5 volts which ought to work fine. 

First connect the ground buss of the KEFS (Steps 7.F or 7.H) 
to the (-) terminal of the 5-v power supply. Then connect 
the KEFS +5v power lead (Step 7.E) to the (+) terminal of the 
5-volt power supply. 

NOTE: If you're using the scanner's power supply, BE SURE THE 
SCANNER IS TURNED OFF. Position the KEFS board near, but not 
in the scanner, and then connect the KEFS ground buss to the 
scanner's metal chassis somewhere. An alligator clip lead 
will do nicely. Then connect the KEFS +5v power lead to the 
OUTPUT lug of IC-8 in your PRO-2884/5/6. A temporary solder 
connection will be better than an alligator clip lead here to 
prevent accidental shorts h. embarrassing smoke. 

9. Connect a handy length of hookup wire to the (+) terminal of 

the power supply. If you're using the scanner's power supply, 
then connect this wire to the same point as the KEFS +5v power 
lead in Step 8. Then solder a 1, 038-ohm resistor (1-ki to the 
free end of this wire. NOTE: This is a temporary step for 

test purposes only. This 1-k resistor and wire will not be 
needed later. 

13. If you have a mi Hi ammeter available, connect it in series 
with the (+) power supply lead to determine current flow. If 
you don’t have a milliasmeter, don't worry. Turn the +5v Test 
Power Supply On (or the scanner, as appropriate). Be real 
nervous at this point while you check for smoke or other weird 
effects in case something went wrong. The LEDs should be OFF. 
If you have a milliammeter connected for current measurement, 
check to see that current drain is less than one milliamp. 
Anything more than 1 to 5-ma indicates a problem. Actually, 
if all is well, the milliammeter should indicate virtually 
zero after a few seconds have lapsed. If something appears to 
be wrong at this point, shut off the power and troubleshoot 
your KEFS Board. If all appears ok, then proceed below. 

11. Assuming that all appears ok at this point; i.e., minimal 
current drain and no LEDs lit up, momentarily touch the 1-k 
resistor connected in Step 9 to Pin 1 or 2 of U-l on the KEFS 
Board. LED n A a will light up! It might momentarily light or 
flicker and then go off. This is due to the “noise" caused by 

touching the 1-k resistor to U-l 's pins. Not to worry. 
Practice this a little, and you'll see where a quick, firm, 
momentary touch of the 1-k resistor to Pin 1 or 2 of U-l will 
turn on LED "A”. Now touch the 1-k resistor again to Pin 1 or 
2 and LED “A" will extinguish. This simulates a push-on, push 
off action which will be done by the Keyboard buttons later I 
If ail is well, at this point, touch the 1-k resistor to Pin 4 
or 5 of U-l and note that LED "B“ can be controlled similar to 
the first. Repeat this test procedure for Pin 9 or 18 and 

again for Pin 12 or 13 to test the action of LEDs "C“ St "D“. 

Now, turn the power supply or scanner OFF; wait a minute or 

so, and then turn it back on again. All LEDs should be 
extinguished. Proceed below. 

12. If you did not opt for the LED Indicator, or if you 

successfully performed Step 11, then do this Step now. 
Connect an ohmaeter or other continuity tester to the wire 

pair at U-4, Pins 1 & 2. Repeat the procedures in Step 11, 
except watch the ohmseter which should indicate an open 
circuit (infinity ohms). Now touch the 1-k resistor to Pin 1 
or 2 of U-l, and note that the continuity tester will show a 
path, just like a switch was closed! If using an ohmaeter, 
the resistance will be between 188-380 ohms. This is normal. 
Now again touch the 1-k resistor to Pin 1 or 2 of U-l and see 
that the continuity tester or ohmaeter again reads an open 
circuit. If all is well, at this point, connect the ohmaeter 
to the wire pair at U-4, Pins 3 St 4. Touch the l-k resistor 
to Pin 4 or 5 of U-l and note that the ohmaeter can be 
controlled similar to the first. Repeat this test procedure 
for U-l, Pin 9 or 18 and again for Pin 12 or 13 to test the 
action of the 3rd and 4th Switch Segments, U-4, Pins 8 St 9 and 
Pins 10 St 11. Just like in Step 11, this simulates a push-on, 
push off action which will be done by the Keyboard buttons 
later! This step tests the action of the 4866 switch, so if 
all is well at this point, you're done and ready to install 
the KEFS board in your scanner. 

13. Remove the temporary 18-k resistors from the ends of the wire 
pairs that go to U-l (Step 7.1). Separate the twisted ends of 
the wire pairs and clip off all but about l / 8 a of exposed 
wire. Tin with solder the exposed end of each of the eight 
wires. Remove and discard the 1-k resistor and temporary 
hookup wire (Step 9). 


It is impossible to cover precise installation procedures for ail 
scanners but the following steps will cover the Realistic 
PRO-2884, 2085 and 2336. With some variance here and there, many 
other Realistic scanners can be readily adapted to accept the 
Keyboard Extended Function Switch. Chances are that any scanner 
with adequate space to hold the KEFS and which has a matrix type 
of keyboard with at least a CLEAR and/or ENTER key can also accept 
the KEFS. The following procedures are specifically for the 
PRO-2084/5/6 and will be followed up with general suggestions for 
other scanners. 

14. Find a suitable mounting location for the KEFS board in your 
scanner. Wire length is not critical, so anywhere there is 


K1K3 - Page 4 

room will be ok. Just keep in mind that you say be making 
numerous modifications to your scanner in the coming months, 
so don t squander what little “real estate 9 is available. 
Make your installation neat and conservative. Connect the 

KEFS ground buss (or stiff copper wire) to a scanner ground, 
either the metal chassis or a printed circuit board ground 
trace. Mount the KEFS in the scanner now. 

15. Connect the +5v power lead of the KEFS (Step 7.E) to the 
scanner's +5v power supply. This is the OUTPUT lug of IC-8. 

16. If necessary, remake the LED Indicator Assembly (Step 7.K) so 
that it conforms to a nice appearing arrangement for the front 
panel of your scanner. If you don't know how to go about this 
aspect of the installation, please wait for my forthcoming 
SCANNER MODIFICATION HANDBOOK, Vol-2 which shows in great 
detail how to install T-l LEDs in the faceplate of the 
PRO-2804/5/6 and other scanners. Otherwise, install the LED 
assembly in the face plate of your scanner at this time. It 
may be convenient to temporarily remove the wiring from the 
LED Assembly to facilitate installation. Reconnect the wires 
per Step 7.K. after the LED Assembly has been installed. 

17. Group and bundle together the four wire pairs (Switched wires) 
from U-4. These wires will serve as the switch connections 
for any modifications or controls that you wish to incorporate 
into the KEFS. Position this wire bundle out of the way for 
now. Tape off the ends of any pair you won't be using. They 
will always be available for future needs! 

IS. Group and bundle together the four wire pairs (Keyboard 
Control) from U-l. Identify the individual wires that go to 
U-l, Pins 1, 4, and 9. Twist together and solder the stripped 
ends of these three wires. Strip the ends and prepare the 
remaining five wires as follows: twist together and tin with 
solder the ends of the two wires that go to U-l, Pins 2 and 
13. Also twist together and solder the ends of the two wires 
that go to U-l, Pins 5 and 12. Leave free the remaining wire 
that goes to U-l, Pin 18. 

19. PRQ-2004 - Only: Turn the scanner upside down so that you can 
see the inside area just behind the Keyboard. Locate the 13 
solder pads in a vertical line along the right edge of the 
Keyboard circuit board. The closest spot is Pad 13. The 
deepest, most difficult to get to is Pad 1. 

A. Solder the wire from U-l, Pin 18 (Step 18) to Keyboard Pad 9. 
This is the numeral n 3 a key pad. 

B. Solder the two wires from U-l, Pins 2 It 13 (Step 13) to 

Keyboard Pad 18. This is the PROGRAM key pad. 

C. Solder the two wires from U-l, Pins 5 St 12 (Step 18) to 

Keyboard Pad 11. This is the ENTER key pad. 

D. Solder the three KEFS wires from U-l, Pins 1, 4 St 9 (Step 18) 

to Pad 12 of the Keyboard. This is the CLEAR key control pad. 

28. PRQ-2005/6 - Only: Facing the front of the scanner with the 
top cover removed, look immediately behind the number 1, 2 St 3 

keys inside the front panel where you'll see a white connector 
strip, CN-501. Looking down from the top, the closest pin of 
CN-501 to the metal side chassis is Keyboard Pin 1. The 
opposite end pin of CN-501 is Pin 13. Cut four pieces of 
stiff, bare copper wire, 18-22 ga, about 1 / 2 U to s / 8 “ long. 
Insert one of these short copper stubs into Keyboard Pin 12. 
Grip this wire stub with a forceps or needlenose pliers and 
work it gently but firmly into Keyboard Pin 12 until it seats. 
It might help to first practice with a sewing needle or a pin 
until you can see how an insertion can be made. Then, insert 
the remaining three stiff copper wires into Keyboard Pins 11, 
10 and 9 respectively. When properly inserted, these four 
short copper stubs will be firmly seated and cannot “fall out 9 
without a definite pulling force. 

A. Solder the three KEFS wires from U-l, Pins 1,4 Sc 9 (Step 18) 
to the stub in Keyboard Pin 12. This is the CLEAR key control 

B. Solder the two wires from U-l, Pins 5 St 12 (Step 18) to the 
stub in Keyboard Pin 11. This is the ENTER key pin. 

C. Solder the two wires from U-l, Pins 2 St 13 (Step 18) to the 
stub in Keyboard Pin 10. This is the PROGRAM key pin. 

D. Solder the wire from U-l, Pin 18 (Step 18) to the stub in 
Keyboard Pin 9. This is the numeral "3“ key pad. 

That's it; your KEFS is fully installed and operational. 


You'll have to study the Keyboard Switch Matrix in the Service 
Manual for your scanner. If your scanner has, say fifteen keys, 

they might be electrically arranged in a matrix cf 3 x 5, that is 

three rows by five columns. The probable connection points for 
the KEFS will likely be to the narrowest dimension of the matrix. 

Therefore, if yours is a 3 x 5 matrix, you'll only be able to get 

two switch functions from dual keypresses. There are only two 
combinations of two switches in a 3-row matrix. So you'll not be 
able to use all four switch segments of the KEFS if this is so. 

The PRO-2804/5/6 have a 4 x 8 matrix so there are a total of six 

possible pairs of switching in a four row matrix. In general, do 
not attempt to connect your KEFS to the widest dimension, thinking 
that there will be more combinations; there will not! The columns 
or widest dimension of a Keyboard Switch Matrix usually have a 
full-time 5-volts; the rows or narrowest dimension is almost 
always 3-volts until contacted by the columns. This is the logic 
basis of the KEFS, you see. The inputs of U-l must always be 
"Low 9 or 8-volts except when a keyboard pair is pressed. So, in 

the final analysis, you may have to test your Keyboard Matrix with 

a voltmeter to determine which rows/columns are “Low" and which 
are "High”. The KEFS must be connected to "Low" keys. One other 
thing: your scanner must have a 5-volt power supply or else my 
KEFS will not work. Most scanners nowadays do, so this should not 
be a problem. If in doubt, I will be glad to offer suggestions and 
a professional opinion on the suitability of my KEFS with your 
scanner. You MUST, however, enclose a SASE and one loose extra 
stamp with your request. Also, send me a copy of the Service 
Manual for your scanner or the schematic diagram, if I don't 
already have one. I do have manuals for most current Realistic 


- Page 5 

scanners and the BC-768/953, BC-238/205 and a tew others. I can't 
help you here without benefit of a diagram or a Service Manual. 
Besides all that, you can t help vourself without the diagram and 
Manual, so you better have 'em regardless of whether or not you 
need my help! 


The KEFS is capable of turning on or off most low current 
circuits, and switching in or out virtually all low-level signal 
paths. There is an inherent resistance of around 258-ohms in each 
segment of the 4866 Bilateral Switch chip, so this limits the 
amount of current that can flow through the 4866 without burning 
it up. This limit appears to be about 28-ma; possibly 25-ms. The 
4866 is cheap, though, so if you burn one out, just replace it. 
You can parallel switch segments for increased current handling if 
necessary, but there is a better method that I will show you next 
month. It involves a simple circuit of one transistor and one 
resistor to allow current drains of 108-ma or more. 

Another limitation of the KEFS as presented this month is that the 
4366 Bilateral Switch cannot switch voltages higher than the power 
supply voltage or else it will burn out. While the 4866 can be 
powered by up to 12 volts, my KEFS is powered by 5 volts, so you 
can't use it to directly switch 12-volt circuits. Relax, because 
the add-on circuit I'll show you next month will not only handle 
higher currents but also voltages to as high as 25 volts or so 
which is well beyond anything you'll encounter in your scanner. 
Most of our switching needs are for 5-volts, which makes the KEFS 
eminently suitable for most applications and next month. I'll show 
you how to adapt one or more switch segments for higher voltage or 
current needs. 

As depicted and designed here, the KEFS is not well suited for 
switching RF signals. RF is susceptible to degradation by lengthy 
wire runs, so don't attempt to use it as a "Crystal Switch", a 
better approach for which is discussed in "Professor Peabody’s" 
article this month. The 4066 Bilateral Switch chip can handle RF, 
but it must be laid out differently than in the KEFS, which was 
designed to switch DC power, digital and audio signals only. 


By now many of you hackers have changed the CPU Clock resonators 
to increase the SCAN k SEARCH speed of your scanners. Typical is 
38-cps for the PRO-2884/5 and 45-cps for the PRO-2096. The PRO-34 
can be cranked up to maybe 28-25-cps, and the BC-288XLT speed can 
be doubled at least. This is a great mod but it has one liability: 
shortened DELAY time. But it is possible to gang your Clock 
crystals on a switch so you can select original speed and delay; 
faster speed but shorter delay, and/or you can always put in a 
lower freq crystal than stock if you wish. One example of why 
you'd want a slower mode sometimes is the military aircraft band, 
225-488 MHz. NFM is the default mode for this band in the 
PRO-2884/5/6. But AM is the most commonly used mode here. So if 
you program 100 military aircraft freqs, you have to change modes 
198 times, with lots of chances for error. Don't forget, DELAY 
has to be programmed too. Instead of "boinkinq" the manual button 
188 times to check programming, just put the slowest speed into 
operaton and watch the display. Any errors can be quickly found 

and corrected. Plus, wear on the keyboard and your finger are 
reduced. A 5 MH: crystal will create a longer DELAY than the 
stock 7.37 MHz crystal. But speed will be lowered to 13 CPS in 
the PRO-2904/5. But no matter how you want to tailor the speed, 
the big word here is versatility! Choose the soeed for the mode 
you select. Crystal switching can be easy; all you need is a 3PDT 
switch such as Radio Shack's sicroaini toggle, catalog 1275-625; 

wired as shown. _ ^ 


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On* caution if you use the stock resonator: DO NOT SOLDER the 
center pin back to ground. Leave it open and just use the two 
outside pins. Otherwise the resonator will override the other 
crystal. The switch should be mounted any place convenient on the 
front panel. The best place for a toggle switch in the PRO-2985/6 
is along the vertical groove that separates the Keyboard from the 
LCD Display area. There is a problem with the PRO-2084 since the 
Clock resonator is not physically near the front panel like in the 
PRO-2805/6. i*le have to keep the wires as short as possible 
because of the RF generated by crstals. A coming article will 
present a "diode" switch that will be suitable for any scanner, 
regardless of where the Clock crystal is located. For now, and 
for the PRO- 2885/6, be sure to insulate the crystal body with tape 
to protect it from shorting out something on the CPU board. 



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©-If? I FEB 18 139) 


PO BOX '262478 


1/1 N3 - Page 7 


NAME: - 






RADIO INTERESTS? (Put YEARS OF EXPERIENCE in each block that applies; 
VHF-UHF Amateur CB Shortwave Professional 

Scanning? Radio? Radio? Listening? Radio? 


Or Occupation: 

List the make k model of your scanners and other radio equipment: 

Single copy, per issue $4.00 $4 surf/$5 Air 

1991 (6 sas,Jan-June) $15.00 $17 surf/$22 Air 

1991 (1 yr) Jan-Dee $25.00 $30 surf/$38 Air 

1991-92 (2 yrs) $45.00 $55 surf /$78 Air 

Other Available Literature 

scanner m nndbk, m-i: $17.95 + $3.00 s&h* 

SCANNER HDD HNdEK, Vol- 2 : $17.95 + $3.00 S&H* 

*<Canada $4 S&H; Other Foreign $5 S&H; Air Hail extra) 


Use the below space to tell us anything else you want! 

List the make k model of any computer equipment you own/operate: 

Enclose a it 1 0 S.4.S.E. znd_ one loose extra stain if you 
need other intonation or a personal reply/ 

KfcVO^Afl) fOtJersQfJ Suj'TCrf UJ/A/UG- 7>A?-//-/P7 

"THE WORLD SCANNER REPORT" (c) 1991 VI N3 - Page 8 

PO BOX 262478 
SAN DIEGO, CA 92196-2478 


billiard* •••offering ••• rouutu 


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